Nano Archive

Electrostatic gating of a nanometer water channel

Li, Jingyuan and Gong, Xiaojing and Lu, Hangjun and Li, Ding and Fang, Haiping and Zhou, Ruhong (2007) Electrostatic gating of a nanometer water channel. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 104 (10). pp. 3687-3692.

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Official URL: http://www.pnas.org/content/104/10/3687.abstract

Abstract

Water permeation across a single-walled carbon nanotube (SWNT) under the influence of a mobile external charge has been studied with molecular dynamics simulations. This designed nanopore shows an excellent on–off gating behavior by a single external charge (of value +1.0e): it is both sensitive to the available charge signal when it is close (less than a critical distance of 0.85 Å or about half the size of a water molecule) and effectively resistant to charge noise, i.e., the effect on the flow and net flux across the channel is found to be negligible when the charge is >0.85 Å away from the wall of the nanopore. This critical distance can be estimated from the interaction balance for the water molecule in the SWNT closest to the imposed charge with its neighboring water molecules and with the charge. The flow and net flux decay exponentially with respect to the difference between these two interaction energies when the charge gets closer to the wall of the SWNT and reaches a very small value once the charge crosses the wall, suggesting a dominating effect on the permeation properties from local water molecules near the external charge. These findings might have biological implications because membrane water channels share a similar single-file water chain inside these nanoscale channels.

Item Type:Article
Uncontrolled Keywords:carbon nanotube; molecular switch; nanogate
Subjects:Physical Science > Nano objects
Analytical Science > Nanotechnology for sensing and actuating
Biomedical Science > Nanoscale biological processes
ID Code:3161
Deposited By:Anuj Seth
Deposited On:26 May 2009 11:41
Last Modified:26 May 2009 11:41

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